X-ray structure analyses of tRNA and aminoacyl tRNA synthetase are being performed, along with related solution structure studies. The latter include NMR studies of tRNA in solution, studies of tRNA-complex cation interaction, synthetase sequence and reactivity studies, etc. The nature of the folding of RNA chains and the potential for non-Watson-Crick base pairs in the helical regions of RNA are also under investigation, as well as proteins that facilitate the kinetics of correct folding of RNA molecules.